Seal-to-shape blister package

ABSTRACT

A package is disclosed comprising a blister attached to a paperboard card, wherein the paperboard card has a curved shaped.

REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. §119(e) of provisional application Ser. No. 61/365,466 filed on Jul. 19, 2010 which is hereby incorporated by reference in its entirety.

BACKGROUND

The present application is directed to paperboard packages and more particularly to self-standing features for paperboard packages.

Manufacturers and retailers of consumer goods, such as pharmaceuticals, software, electronics, health and beauty products and the like, typically package their products in tamper resistant security packages. For example, many consumer goods are packaged in blister or clamshell packages formed by positioning a consumer good in a flanged blister made from various polymeric and/or paperboard materials and sealing the flanged blister between two paperboard substrates. Consumers have voiced disapproval of such packages because of the difficulty of opening the same and the potential for being cut on a rough edge especially of plastic blisters. Packages may therefore be made based largely on paperboard, for example, NATRALOCK packages. Packaging made primarily of paperboard is more sustainable than packaging made from petroleum-based plastics. The paperboard used in such packages may be tear-resistant as described in commonly assigned U.S. Pat. No. 7,144,635.

Some blister packages may comprise a paperboard card and a blister. Such a package may be suitable for display by hanging from a hook, but may not be well adapted for display in a standing configuration.

International Application PCT/US09/067004, which published as WO2010068593 and is hereby incorporated by reference in its entirety, describes a package utilizing folds in a paperboard substrate to form various standing configurations.

The current application discloses additional packages including a package utilizing a curved paperboard substrate.

SUMMARY

In one aspect a packaging structure is disclosed which comprises a first panel and a second panel comprised of sheet material, and a first blister sealed to or formed as part of at least one of the panels, and wherein the first panel and the second panel are sealed together along a curved interface.

In another aspect a packaging structure is disclosed which comprises a first panel and a second panel comprised of sheet material, and a first blister sealed to or formed as part of at least one of the panels, and wherein the first panel and the second panel are sealed together using radio frequency heating.

Other aspects of the disclosed packaging structures will become apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of a blank for a packaging structure;

FIG. 1B is a side perspective view of the blank of FIG. 1A, along with a blister to fit therein;

FIG. 2A is a side perspective view of a partially package made from the blank and blister of FIG. 1B;

FIG. 2B is a side perspective view of a completed package made from the blank and blister of FIG. 1B;

FIG. 3A is a perspective view of parts for another packaging structure;

FIG. 3B is a side perspective view of a package made from the parts of FIG. 3A;

FIG. 3C is a top perspective view of a package made from the parts of FIG. 3A;

FIG. 4A is a perspective view of parts for another packaging structure;

FIG. 4B is a top perspective view of a package made from the parts of FIG. 4A;

FIG. 4C is a cross section view of a package of FIG. 4B; and

FIGS. 5A-5C are cross section views at various elevations of the package of FIG. 4B and a tool for making the package.

DETAILED DESCRIPTION

As various embodiments of the security package are described, reference will be made to FIGS. 1-5. Certain parts of the packages are denoted by reference numerals. Where there is more than one of the same feature, generally only one will be denoted by a reference numeral. If different packages have a common feature, it may only be described one time. Common features, where practical, are denoted with similar numerals differing by the ‘hundreds’ digit. For example the back panel shown in FIG. 1A-1D is back panel 120; while the back panel shown in FIG. 3A-3C is back panel 320. Typically in these Figures, where a top plan view is shown for a blank of material, solid lines indicate periphery or cuts, and dashed lines indicate crease, score, or fold lines. In perspective views, solid lines typically show edges, while dashed lines typically show hidden or partially obscured features. Where assembly steps are described, these steps are exemplary and are not to be limiting as to the sequence of operations used to arrive at the final package. Also, directions such as up, down, top, bottom, front, back, etc. are used for convenience in describing the package and are not meant to be limiting. In most cases the packages described here are made from one or several blanks (that is, the cut sheet parts from which the package components are made by folding and other steps). However, it should be understood that certain unitary blanks may be provided instead as more than one part, and certain blanks may be combined into single blanks, while still arriving at the same finished package. The word “panel” will often be used to describe a piece of sheet material such as paperboard, particularly with respect to a blank from which the package is made. However, “panel” may also be used to describe a region of a piece of material, for example a portion of the material that is in a first plane, connected across a fold line with the same material in a second plane. Since panels are sometimes superimposed, for example, creating a two-layer structure, like features or panels will sometime coincide, in which cases, descriptions may call out the number identifying the feature closer to the viewer, that is, the feature visible in a particular Figure.

Paperboard security packages, such as blister packages, are well known by those skilled in the art. FIGS. 1A and 1B show plan and perspective views, respectively, of a card 110 for forming a known security package, for example as described in U.S. patent application Ser. No. 11/924,750. Also shown is a blister 160 to fit within the card. The blister may be a recycled material such as RPET or a biodegradable material such as PLA. However other materials including other plastics or paperboard may also be used. The card may have a back panel 120 and a front panel 140 and one or both of these panels may comprise a hang hole 121, 141. If both panels have hang holes, they may overlap to provide two layers of material to reinforce the hang hole and surrounding area. A reinforcing layer of paperboard or other material may be placed between the front and back panel, for example at the hang hole location, as described in PCT/US08/066517. The front panel may have an aperture 144 to receive the body 162 of blister 160. Blister 160 may have a peripheral flange 164 to be sealably received between the back panel 120 and front panel 140.

FIG. 2A shows a perspective view of the package in a partially assembled configuration, with blister 160 placed upon back panel 120, and front panel 140 in the process of being folded over the blister and back panel. As seen in FIG. 2A, and also in the finished package 100 of FIG. 2B, the body of blister 160 fits in aperture 144, while the flange 164 becomes sandwiched between front panel 140 and back panel 120.

The card 110 (and other cards, sleeves, liners, wraps, etc described herein) may be formed of a sheet material such as paperboard, which may be made of or coated with materials to increase its strength. An example of such a sheet material is EASYSEAL paperboard made by MeadWestvaco Corporation. The sheet material may have a heat sealable coating, for example to allow a heat seal to be created between the back panel 120 and front panel 140. Alternately, other forms of adhesive may be used to seal these panels together. It should be noted that the use of tear resistant materials, and/or in more than one layer, help to improve the tamper- and theft-resistance of the package.

Package 100 may be used to enclose either a loose item of merchandise, or an inner carton enclosing merchandise. For example, a manufacturer may have an existing well established carton with a well-recognized brand image, but lacking adequate security. Such a carton may have a premium appearance, for example custom graphics, metallization, embossing, or other premium features. By placing the existing premium carton inside the security package, tamper and theft resistance are provided. Furthermore once the security package is opened (which may destroy the security package) the premium package is still intact. Thus a manufacturer may wish to enclose an existing carton within package 100, or any of the other security packages described herein.

The following packages and blanks disclosed in this application teach modifications on the standard paperboard blister packages. The disclosed modifications teach improved standing features for a paperboard based package. It is to be understood that a variety of materials may be used to form these packages. However, for sustainability purposes, a paperboard based material may be used and for improved theft deterrence a tear resistant paperboard may be used. The standing features described in this application may be used alone or in combination with other package features.

FIG. 3A shows a perspective view of parts for forming another standing package. The parts may include back panel 320 with back side panels 320A, 320B; a front panel 340 with front side panels 340A, 340B, and a blister 360 with a blister body 362 and flange 364. One or both of the front and back panels may comprise a hang hole 321, 341. If both panels have a hang hole, they may overlap to reinforce the hang hole and the surrounding area. The front and back panel may be provided with fold, crease or score lines (generally shown, with fold line 320F enumerated as an example). To facilitate folding, clearance slots 342 may be provided on fold lines. Blister 360 may be provided with blister flange 364 that may be sandwiched from behind by back panel 320 and back side panels 320A, 320B; and from in front by front panel 340 and front side panels 340A, 340B. Aperture 344 may be provided in front panel 340 through which blister 360 may protrude. Blister flange 364 while being generally flat may lie in more than one plane. The shape of the blister flange 364, including one or more flange folds, may be used to help retain the finished package in a particular shape.

FIGS. 3B and 3C show the assembled package in front perspective and top perspective views. The (now hidden) blister flange 364 is shown (dashed lines) sandwiched between the layers of the front panel and back panel. The angle between panels 340, 340A, and 340B, along with the size of the side panels relative to the package and the blister, may be chosen so that the center of gravity of the finished package falls within the “footprint” defined by the front/back panel and the side panels. Thus the package will stand upright and stable. Alternately the package may be displayed hanging from hang hole 341.

It is to be understood that the hang tab may comprise two or more layers of material. It is to be understood that the hang tab may comprise three or more layers of material. It is to be understood that the exact dimensions of the package may be adjusted based on manufacturing preferences. In addition, fold-over panels may be provided on some paperboard panels to strengthen certain areas, for example the hang tab, by adding one or more layers. In such an instance a heavier product may be contained within the package without risk of the hang tab tearing or breaking These packages may be formed from more than one blank of paperboard material, or the blanks may in some cases be combined. In some cases, the packages may be formed from a single blank of paperboard material. The blank or blanks may in some cases be folded to create the package. In some cases, the packages may be formed using a single layer of paperboard material.

Fold lines in certain of the package designs may provide an area through which to initiate a tear. To help prevent such a tear or keep it from breaching the blister, stress diverter features (not shown) may be provided such as shaped openings along a fold line to divert a tear away from the blister. One or more layers of the paperboard (any in any of the packages) may have one or more overt (visible) or hidden features to help deflect any initiated tear back toward the outside periphery of the package, or otherwise away from the contents. For example, partially-cut lines may be made into a hidden surface such as the inward-facing surface of the front panel or back panel, so that if a tear is initiated, the hidden partially-cut line may divert the tear back toward the edge of the package. Such tear-diverting features are described in U.S. Provisional Application No. 61/081,404.

A tear proof material such as DURAFOLD paperboard will usually need to be opened using a tool such as a knife or scissors. Tear resistant material such as NATRALOCK may be provided with overt or hidden features to assist a customer in opening the package, as described in U.S. Provisional Application No. 61/025,102. Such opening features may be incorporated in any of the packages disclosed herein.

The adjoining surfaces of front panel 340 and back panel 320 may be adhered together by heat sealing, gluing, or other adhesive. Back panel 320 and front panel 340 may, for example, be paperboard. The panels are shown with substantially the same perimeter, which may yield a package comprised of two layers of paperboard. However, portions of the package might only be single ply. A more secure package may result if the blister flange 364 is sandwiched between two layers of material. One or both plies may comprise hang hole 341.

Heat sealing may be accomplished by use of both heat and pressure. Heat sealing may be used at the juncture of blister flange 364 with the front panel 340 and back panel 320. Heat sealing may also be used along the periphery of front panel 340 and back panel 320. Alternately heat sealing may be used on the entire adjoining surfaces of front panel 340 and back panel 320, including the blister flange 364.

FIG. 4A shows a side perspective view of parts for forming another standing package. The parts may include a back panel 420 and a front panel 440. The terms “back” and “front” are not meant to be limiting. The front and back panels may comprise hang holes 421, 441. The package may also comprise front blister 460 with blister body 462 and blister flange 464.

The front panel 440 and back panel 420 may be identical or nearly identical as shown in FIG. 4A, thus resulting in a package whose paperboard components are for the most part two-layer. However, certain of the paperboard panels may be omitted, resulting in a package with some single layer areas. It may be advantageous for at least front panel 440 and back panel 420 to be provided so that blister flanges 464 may be sandwiched between layers of paperboard as shown.

The combined front panel 440, back panel 420, and blister 460 may be used to form a curved package, that is, a package with at least one of the front and back panel defining a curved surface in the finished package. The blister flange 464 may be curved so as to easily be sandwiched between front panel 440 and back panel 420 when a curved package is created. Depending on the package design, that is, whether the package is curved toward the front as shown in FIG. 4A, or curved toward the back (not shown). The package may also be curved in other shapes, for example in an S-shape.

If the package curved toward the front as in FIG. 4A, front panel 440 may have a width W2 slightly less than the width W1 of back panel 420 so as to cause the package edges to be lined up after assembly. The package edges may be trimmed after assembly.

FIG. 4B shows a top perspective view of the package in an assembled configuration. It is seen that blister body 462 of blister 460 may fit through aperture 444 in front panel 440.

FIG. 4C shows a cross section through the finished package (for example along line 4C in FIG. 4B), which may have a curved shape, for example curved to the front as shown, although a curve toward the back is likewise possible, as is more complex curves such as an S-curved shape.

One way to form the package shown in FIGS. 4B and 4C is to apply adhesive between the front panel 440 and back panel 420, and then to seal the two panels together trapping the blister flange 464. However, in such an assembly, it may be necessary to hold the parts together until the adhesive sets. Alternatively, a heat sealing process may be used, for example applying a front and back platen to the assembly, and applying pressure, with at least one of the front and back platens being heated. In such a process a finite time is required for heat to penetrate through the panels 420, 440 and soften the adhesive therebetween. However, with the curved configuration, the front and back panels after heat sealing may tend to straighten out if the platen pressure is removed before the adhesive cools. This may result in the package delaminating, that is, the adhesive releasing and the panels 420, 440 separating. To avoid this, the platens may maintain pressure until the adhesive cools. However, the hot platen(s) used in such a process means that cooling can be slow. This could result in a relatively slow heat-sealing process.

Instead of conducting heat from the platen and through the covers to the adhesive, radio frequency (RF) energy may be applied to seal the package by use of a suitable platen or platens. The RF energy (including the wavelength) and the adhesive material may be chosen so that sealing energy is applied without the platens becoming hot, that is, without the platens approaching the melting temperature of the adhesive. In such a process, once the RF energy has melted or otherwise activated the heat seal or other adhesive, the RF energy may be discontinued. The adhesive may then cool quickly and set or solidify, since the platen may operate at a relatively cool temperature and not delay setting of the adhesive. As an alternative method, thermal impulse sealing may used, which involves rapid heat-up and cool-down to speed the sealing process.

FIGS. 5A-5C show cross section views of front platen 502 and back platen 504 enclosing back panel 420, front panel 440, and blister 460. The cross sections correspond to section lines 5A, 5B, and 5C in FIG. 4B.

FIG. 5A shows that at certain elevations of the package, for example the upper edge or lower edge (or the side edges) the back panel 420 and front panel 440 contact each other without any blister flange in between. In such areas, platens 502, 504 may simply apply pressure and RF energy, for example applying these uniformly across the adjoining surfaces, although the pressure and RF energy need not necessarily be constant across the package. The applied pressure and energy may be adjusted by adjustment of the applied force on the platens and the applied electrical energy, as well as the clearances of the platens and the design of the RF heating equipment. Pressure and energy may be applied evenly across critical seal areas by way of patterned and machined tool surfaces.

FIG. 5B shows that at certain elevations of the package, for example the upper edge or lower edge of the blister, the back panel 420 and front panel 440 contact each in some areas without any blister flange in between, and in other areas a blister flange 464A may be sandwiched between the panels. The platens 502, 504 may be designed (for example with appropriate clearances), and the applied force and RF energy may be chosen, to apply the appropriate pressure and RF energy to the differing areas of the package. For example it may be desired to leave enough platen clearance in areas enclosing blister flange 464A, to prevent thinning of the flange in instances where the RF heating may temporarily melt or soften the flange material. However, in some instances a small amount of thinning may be tolerated or even desired, in which case less platen clearance might be chosen.

FIG. 5C shows that at certain elevations of the package, for example the central areas of the blister, the back panel 420 and front panel 440 contact each in some areas without any blister flange in between, while in other areas a blister flange 464B may be sandwiched between the panels, and yet in other areas (e.g. the main part of the blister) there may be no contact between any of the three components (front panel, back panel, or blister). The platens 502, 504 may be designed (for example with appropriate clearances), and the applied force and RF energy may be chosen, to apply the appropriate pressure and RF energy to the differing areas of the package. For example, the platens may be designed so that in the area of flange 464B there is higher pressure and/or RF energy to ensure sealing in that area. On the other hand it may be desired to have little or no pressure and /or RF heating of blister body 462. The front platen 502 may be designed with a platen cavity 510 to receive blister body 462. The platen cavity 510 may be slightly oversized to avoid contact with blister body 462. It may be appreciably oversized to allow the platen to be used with blisters with various depths of blister body 462.

To use the RF heating to seal the package, the back panel 420, blister 460, and front panel 440 may be placed between platens 502, 504. The platens may then be closed and RF energy applied to seal the panels and blister together. Pressure may be applied to the platens. The adhesive between platens 502, 504 may be chosen with suitable properties, that is, susceptibility to RF heating, suitable melting point range, suitable strength, etc. Preferably RF energy may only be applied for a short duration and preferably the platens may not themselves become very hot, so as to hasten the set time of the adhesive in order to allow a short cycle time.

The front panel 440 and or back panel 420 may be made of a sheet material, for example paper or paperboard. A suitable material is MeadWestvaco NATRALOCK® board. This board delivers excellent RF sealing efficiency and bond strength. NATALOCK® GTR board uses a BPET (branched polyethylene terephthalate) film for tear resistance and a low temperature heat seal coating. The BPET film contains a molecular structure that is excited when RF energy is passed through. This results in a low temperature adhesive (activated around 160° F. to 180° F.) which means the adhesive may be activated without applying excessive heat. The properties of the BPET film and its low heat seal temperature allow the RF sealing process to achieve sealing without a thermal energy pre-heat cycle. RF sealing of NATRALOCK requires only internal activation of the coating between the front and back panels. This is an advantage particularly when sealing non-flat shapes since the internal stresses of sealing non-flat shapes tends to break the freshly activated seal surfaces if excess heat from conventional thermal sealing is required to dissipate. Another advantage of RF sealing a non-flat package is a short cool down phase of the sealing cycle. During the cool down cycle after application of RF energy, the platens hold pressure on the sealed package for a set time to allow the internal bond to cure and gain strength. A short cool down phase is advantageous.

Designs of the blanks (e.g. paperboard material) for non-flat front and back panels should account for dimensional differences between front and back panel as bending a panel into a three dimensional shape slightly changes the relative dimensions of panels in a non-flat package. Once the non-flat package has been sealed to shape, these dimensional differences between panels help maintain the shape and provide package shape “memory.”

The ability to seal blister card style packages in curved or three dimensional shapes creates a visual effect that may not be possible with two dimensional packages. The composition of the NATRALOCK substrate makes the RF sealing process efficient and seals secure. NATRALOCK's heat seal coating reacts to the RF energy allowing the RF cycle to activate the heat seal and the cool down cycle allows the seal layer to bond maintaining shape after package is released from the platens or other sealing tool. Unlike standard heat seal coated board whose peel force may be one lb or less, the bond strength of NATRALOCK tear resistant board gives a peel force of five to six lbs-force per inch which is good enough for a “fiber tear” (strong) bond.

Examples of materials and processes from which the exemplary packages may be formed are discussed in greater detail in U.S. Ser. No. 11/545,842 filed on Oct. 11, 2006, the entire contents of which are incorporated herein by reference.

The features described in this application may be used alone or in combination with other described standing features or security features. It is to be understood that a variety of materials may be used to form these packages. However, for sustainability purposes, a paperboard based material may be used and for improved theft deterrence a tear resistant paperboard may be used. Package materials may include tear-proof materials such as DURAFOLD paperboard, tear-resistant materials such as NATRALOCK paperboard, as well as other types of paperboard or plastic materials. The packages may be made of one or more layers of material, including but not limited to one, two, three or more layers of material. Different parts of the packages may comprise different materials and/or different numbers of layers.

The packages disclosed herein may be comprised mostly of paperboard, for example as described in International Application PCT/US08/051245. The paperboard used in such packages may be tear-resistant as described in commonly assigned U.S. Pat. No. 7,144,635.

The packages disclosed herein may be made from one or several blanks (that is, the cut sheet parts from which the package components are made by folding and other steps). However, it should be understood that certain unitary blanks may be provided instead as more than one part, and certain blanks may be combined into single blanks, while still arriving at the same finished package.

Where more than one blank is used, the blanks may be assembled in various stages, including assembling a unitary blank into a package, assembling separate blanks and then joining them to form a package, and joining two or more blanks together, for example by heat sealing, gluing, mechanical fastening, or otherwise and then forming the combined blanks into the package.

It is to be understood that certain packages may be one continuous piece of material, and other packages may comprise two or more pieces of material. It is to be understood that a package may be heat sealed even where a heat sealed surface is in contact with a non-heat sealable surface. It is to be understood that in such a situation such an adhesion will strengthen the package, though it may not strengthen it as much as heat sealing between two heat sealable surfaces.

The packages described herein may be assembled in stages at various locations, for example partially constructing the package, moving or shipping it to one or more other locations, and completing the assembly of the package. For example, a package may be formed into a flattened or collapsible structure, then moved or shipped to another location for final forming, filling, and closure.

The packages may be shipped flat and erected when the product is filled or it may be shipped with the tray formed such that the heat sealing only needs to be performed at the edges of the package. It is to be understood that alternate sealing methods may be utilized depending upon manufacturing preferences, and that the package designs may still increase tear resistance in such a case, without the heat sealing. It is to be understood that using heat sealing with the package designs described herein may further increase the tear resistance of the packages.

Portions of the packages may be made of one, two, or more layers of material. It is to be understood that additional layers of material may be used based on manufacturing preferences. Portions of certain panels may be folded over or around the portions of other panels, creating multiple layers of material.

The packages may be provided with overt or hidden features to assist a customer in opening the package, as described in U.S. Provisional Application No. 61/025,102. Such opening features may be incorporated in any of the packages disclosed herein.

The packages may be provided with features to allow opening as described in U.S. Provisional Application 61/025,102. Such features, by way of example, may include overt or hidden weakened areas in the package. Such features may include a cut or nick in the periphery of the package, by which to initiate a tear. Such a tear initiation feature may be covered by a security device.

It should be understood that additional foldover panels may be included in the package blanks for further reinforcing the packages.

Those skilled in the art will appreciate that the disclosed blister packaging structures may provide a theft deterrent function at least for a few moments, while providing legitimate consumers with packages easy to open in a reasonably short time, for example using a pair of scissors and reducing the risk of injury as the scissors are less likely to slip on the NATRALOCK or paperboard like material than on the plastic blister pack.

To provide additional tear resistance protection, any of the materials used in these designs could be provided with overt or hidden features such as nicks, scores, perforations, holes, or other diverting features such that if a tear is initiated in the packaging material, it will not propagate in a direction more likely to breach the package, but may be rerouted by the diverting feature or features in a direction less likely to breach the package. Alternately the diverting feature may stop the tear, slow the progression of the tear, or cause it to take a meandering path, thus lengthening the time it may take to eventually breach the package, and thereby discouraging a thief. Certain tear-diverting features are described in U.S. Provisional Application No. 61/081,404.

It is to be understood that a variety of standing features or a variety of hanging features may be used on any of these package designs as determined by manufacturing preferences. One or more reinforcing layers of paperboard or other material may be placed between layers of a package, for example between the front and back panels of a card-type package, for example at the hang hole location, as described in PCT/US08/066517. The packages may be made to stand upright, either by their general shape, or for example by providing “feet” on the lower portion of blister 160, as described in International Application PCT/US06/030280. Although various aspects of the disclosed blister packaging structures have been shown and described, modifications may occur to those skilled in the art upon reading the specification. 

1. A packaging structure comprising: a first panel and a second panel comprised of sheet material, a blister comprising a flange; wherein the first blister is attached to at least one of the panels, and wherein at least portions of the first panel and the second panel are adhered together along a curved surface.
 2. The packaging structure of claim 1, wherein the blister comprises a flange and the blister is attached to at least one of the panels by use of the flange.
 3. The packaging structure of claim 2, wherein the flange is attached to an interior or exterior surface of at least one of the panels.
 4. The packaging structure of claim 2, wherein a second layer of sheet material is attached to at least one of the panels, and the flange is attached between the at least one panel and the second layer of sheet material.
 5. The packaging structure of claim 1, wherein at least one of the panels comprises a back layer and a front layer.
 6. The packaging structure of claim 1, wherein at least one of the first and second panels comprises a first aperture through which the blister extends.
 7. The packaging structure of claim 1, further comprising a hang hole.
 8. The packaging structure of claim 1, further comprising an overt or hidden tear diversion feature.
 9. The packaging structure of claim 1, further comprising an initiation point from which to start a tear to open the package.
 10. The packaging structure of claim 15, wherein the initiation point is a manufactured cut or nick in the package.
 11. The packaging structure of claim 15, wherein the initiation point is covered or concealed by a security device.
 12. A method of forming a package, the method comprising: providing a first panel and a second panel, both panels made of sheet material, at least one of the panels having a first surface coated by an adhesive, placing the first and second panel in facing relationship with the adhesive between the panels; placing the first and second panels between a first and second platen, applying RF energy to activate the adhesive and bond the panels together; removing the RF energy and allowing the adhesive to set; and removing the panels from the platen.
 13. The method of claim 12, wherein at least portions of the first panel and the second panel are adhered together along a curved surface.
 14. The method of claim 12, further comprising the steps of providing a blister with a flange, and attaching the flange to at least one of the panels.
 15. The method of claim 12, further comprising the steps of providing a blister with a flange, and attaching the flange between the panels. 